Seasonal and latitudinal shifts of the regime of the meteorological North Pacific high result in strong seasonal changes in the California Current system, in which upwelling caused by westward Ekman transport is intensified during the summer at high latitudes and weakened during the winter at low latitudes. Variation in surface biological productivity connected with the upwelling should be recorded in sediment cores in these regions. In fact, the content of biogenic components changed significantly during the last glacial cycle (Karlin et al., 1992; Gardner et al., 1997). We wanted to understand how and why the current systems changed during glacial-interglacial cycles in the late Pleistocene and what processes determine major components in the sediments. For this, we analyzed biogenic components in sediments of Hole 1020B recovered during Leg 167 spanning the last 800 k.y., and we report variations of biogenic components. The site is located on the east side of the Gorda Ridge, 170 km west of Eureka, and has a water depth of 3040 m (Fig. 1).